Frost Dates for 82401 — Worland, Wyoming

Half of springs at Worland, WY see their last 32°F night by May 4; only one in ten is past it by April 23, and one in ten still has one after May 18. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 14 20%, and after May 18 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 58% of the 33 Wyoming stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 21 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 12 days later, around October 13; in spring the one-in-ten date for 28°F is May 8, 10 days before the 32°F one. The freeze-free season lasts 149 days in a typical year, longer than at 97% of the 33 Wyoming stations; it reaches 166 days one year in ten and falls short of 131 one year in ten. On average 182 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about May 16, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 7 and March 18.

July is the warmest month at Worland, WY, averaging 91°F by day and 57°F at night; January is the coldest at 31°F and 4°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 69% of years.

Warmth for growing adds up to 2,558 growing degree days a year (base 50°F), more than at 91% of the 33 Wyoming stations. 30% of them (773) have built up by the end of June, and July adds the most, 741. Precipitation totals 8.5 inches a year, most in May (1.8") and least in December (0.2"); May to September bring 59% of it.

The nearest other station, Thermopolis, WY, 26 miles southwest of Worland and 263 feet higher, has a last frost 1 day later (May 5), a first frost 4 days later (October 5), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Worland usually arrives around November 2, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Rairden 2WSW, WY, 12.9 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 28 days after the last snow.

ZIP 82401 is 1 mile from Worland, WY, which stands at 4,058 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82401 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.